This invention is generally related to exercise devices for muscles surrounding the ball-and-socket joints (or ball joints) of a user, and more particularly, to weight resistance exercise machines for the muscles surrounding the shoulder joints of a user.
The shoulder is the most mobile joint in the human body, with 360 degrees of motion in circumduction, and 180 degrees of motion in all simple radial planes of movement of the joint. The three dimensional range of movement of the shoulder can be mapped as a virtual hemisphere, centered at the glenohumeral joint.
The remarkable range of motion of the shoulder is made possible by minimal static stabilization of the joint. The static stabilizers include bone and non-elastic capsuloligamentous structures. Since the joint capsule and ligaments surrounding the joint are redundant in length, they provide restraint and stability only at wide ranges of motion. The bone structure of the shoulder joint consists of the head of the humerus which glides or rolls in the narrow and shallow glenoid fossa of the scapula. The stability of the glenohumeral or shoulder joint is comparable to the stability of a golf ball (i.e. the humeral head) resting on a golf tee (i.e. the glenoid process).
The biomechanical tradeoff for the tremendous range of motion of the shoulder is minimal static stability. So the shoulder is the most mobile joint, and mutually, it is the least stable joint in the human body as well.
Enhanced dynamic stability, provided by the surrounding musculature (i.e. the dynamic stabilizers), compensates for minimal static stability in the shoulder. From the side view, with the humerus at 90 degrees of abduction, we see a 360 degree radial array of muscles and muscle fibers originating on the trunk, scapula, and clavicle, spanning the shoulder complex, converging and inserting circumferentially into the proximal humerus. Each radial plane of muscle fibers can be recruited to move the shoulder in the coplanar plane of motion. This radial array of muscle fibers about the shoulder also provides coordinated stabilizing radial traction forces throughout the range of motion, in any or all directions simultaneously, for maintaining optimal dynamic alignment of the joint. Therefore, the 360 degree radial array of muscle fibers surrounding the shoulder is the basis for both movement in all radial planes of motion, and for stabilization of the joint in any direction, position, plane, or part of its range of motion. The unique and extensive reliance on radial musculature for 360-degree-motion and stability means that strength training has the potential to provide more effective performance enhancement to the shoulder than any other joint.
The musculature and nervous system respond to training with specific adaptation to specific imposed demand. Training in any specific plane of motion stimulates an increase in strength, stability, and therefore performance in that specific plane of training, with little enhancement of performance in other planes of musculature and motion.
Therefore, in order to optimize strength and stability in multiple planes of motion, the shoulder must be strength trained in multiple planes of movement. For ideal performance gains, for optimal restoration of function after injury, and for maximum protection from instability, the shoulder should be trained in an exponential number of planes of motion throughout its 360 degree radial array of planes of motion about multiple axes.
Six out of ten strength training machines target the shoulder because of the many planes of resisted motion that must be implemented for adequate shoulder training and injury rehabilitation. Theoretically, one should be able to exercise the muscle fibers in every conceivable plane of shoulder motion. However, exercise machines of the past, including the most sophisticated rehabilitation and strength testing devices, have never been capable of practically reproducing the remarkable number of planes of motion of the shoulder. In fact, most shoulder exercise machines are manufactured to build strength in only one or a few standard planes of motion.
Since most prior art strength training machines (and lines of machines) permit exercise in only one or a few planes of motion, specific adaptation (i.e. enhanced strength and stability) occurs only in the same limited number of planes. On past shoulder strength training equipment, the angular distances are large between the conventional, standard radial planes of training. This means performance carryover between these planes of training is minimal. When training is limited to these few conventional planes of exercise, over-training of the musculature occurs in the conventional planes of resistance exercise, and under-training occurs in planes oblique to the conventional planes of exercise. In this way, repetitive training in a limited number of fixed planes of resistance by the prior art paradigm, builds asymmetric strength in the musculature surrounding the shoulder. Asymmetric strength predisposes the joint to instability and injury.
Consequently, training with past equipment leaves the shoulder with less than optimal strength and stability gains, and vulnerable to injury. The limited number of planes of resistance provided by the prior art is a reflection of the unwritten (and erroneous) prior art paradigm that resistance exercise performed through a few standard planes of motion is adequate for building optimal multi-planar strength and stability in the shoulder.
Past exercise machines and equipment, though prolific, employ similar past methods of strength training and assessment. For the purpose of this discussion, the four most important strength training and assessment modalities in use today are: (1) free weights; (2) electromechanical strength training and assessment devices; (3) fulcrum-flexible-linkage strength training machines; and (4) cable functional strength training machines.
Free weights are one of the oldest and simplest tools for strength training and assessment. Free weights are most effective when lifted vertically in a straight line or plane, particularly in compound joint movement. As with all modes of exercise, free weights have limitations. A misconception in the industry is that free weights provide a more functional form of resistance than machines. For example, studies have noted kinetic and kinematic similarities between certain ballistic free weight lifting techniques and sprinting-jumping activities. But utilizing these strength training techniques has not been shown to directly improve functional performance of similar and dissimilar athletic movements in controlled longitudinal studies any more effectively than conventional techniques. The reason for this is that training has very specific effects. Strength training builds strength only in the specific plane and speed of motion of training. And because strength training does not precisely replicate functional, complex multi-planar movement (e.g. skilled athletic movements), it cannot directly enhance performance of functional, complex multi-planar movement.
Shoulder press exercises with free weights, as another example, do not closely simulate any true functional movement, skill, or ballistic motion; nor do free weights closely simulate dynamically varying forces encountered in the real world, any more so than when performing press exercises with other modes of resistance training. So there is little or no greater direct effect on performance when shoulder resistance exercise is performed with free weights as opposed to machines.
In critical comparison to training with presently available machines, training an individual in the skills of lifting free weights has only marginal (if any) added effect on functional performance enhancement for the vast majority of real-world skilled, precision, ballistic, impact, and/or high-performance movements.
Further, in terms of strength assessment, past standard methods do not provide comprehensive physiologic, multi-plane strength data. For example, the standard measure of upper body strength, especially in power sports, has long been the standard horizontal chest or bench press utilizing free weights. (In practice, this frequently results in a misplaced emphasis on building strength in a single plane of motion as the primary goal of shoulder strength training.) Although it is an expedient way of measuring overall strength in a single plane of movement, the bench press does not accurately measure functional strength or stability. A more accurate way to measure overall functional strength and functional stability of the shoulder is to assess strength in multiple planes of radial motion. But there are few strength assessment devices specifically designed for assessing radial strength of the shoulder in multiple planes.
Strength testing devices manufactured today are designed by the model originally established by Cybex, Biodex, and Chattecx active dynamometers, brand names well-known in the strength training and injury rehabilitation industry. These are electromechanical strength training and assessment devices with microcomputer-based feedback and strength evaluation systems. These machines were originally designed to assess knee strength and angular motion in a single plane of movement. Although these machines can be adapted to assess shoulder strength, like free weights, they are not practical tools for assessing strength in multiple planes of motion.
Machines that employ fulcrum-flexible-linkage resistance mechanisms (such as Nautilus and Cybex International machines) provide full and equal tangential resistance through the full arc and range of motion in the plane of exercise. This makes these machines significantly more effective than free weights for isolated resistance training (such as biceps curls), or for any exercise involving an arc of movement. This type of machine can provide isotonic or dynamic variable resistance exercise (e.g. with variable cammed pulleys). These are proven-effective strength building resistance mechanisms and are advantages that free weights cannot provide in an arc of exercise. The major disadvantage of past conventional fulcrum-flexible-linkage machines is that they cannot provide resistance exercise in more than one or a few planes of motion, as discussed previously.
A well-known exercise method called functional training is intended to enhance strength in functional and athletic movements. Cable linkage functional training is performed with machines utilizing an unconstrained user interface (i.e. handhold) directly attached to the end of a weighted flexible linkage or cable. These devices are also called free cable devices, and are descendents of the well-known cable-cross or cable-column type apparatus. Cable functional training equipment (such as that manufactured by Free Motion Fitness and others) operates in a similar manner to past cable strength training equipment, and therefore, is subject to the same limitations. Because of the mechanics of the handhold-cable-pulley mechanism utilized in these machines, cable-cross and free cable functional training cannot provide full and equal tangential resistance through a full arc of motion of exercise, as can fulcrum-flexible-linkage machines. Additionally, past cable machines cannot provide precise alignment and stabilization of the trunk and shoulder in an exponential number of planes of exercise (for precise, reliable targeting and isolation of the exponential planes of muscle action across the joint).
There is disagreement about the influence that any and all forms of strength training may have on injury prevention, specific skills, and sports performance. Most in the industry agree that strength training indirectly improves performance by enhancing joint strength and stability. The idea that strength training can directly enhance actual functional performance is controversial at best.
Generally, strength and stability gains from resistance training do not directly enhance performance. The strength and stability gains resulting from resistance training must be transferred indirectly to functional movement through the process of integration. Integration can be conceptualized as the process of transferring strength, proprioception, muscular coordination, and stability gains from simple, less functional movements, to more complex movements. Pattern integration can also be described as the transfer of enhanced simple pattern neuromuscular function (e.g. as a result of resistance training) into more complex purposeful movement patterns resulting in true functional performance enhancement.
Training in multiple, simple, radial neuromuscular patterns and planes of motion about a joint increases strength and stability more effectively than training in a few fixed planes provided by the prior art. The advantage of resistance training in simple patterns and planes of motion is that the resulting neuromuscular gains are easily integrated indirectly into functional movement, with little or no adverse effect on performance.
It is unlikely that one can directly improve athletic performance by replicating a complex athletic movement using free weights or cable functional training machines. Because the plane of resistance provided by these modes of exercise cannot coincide precisely with that of any real-world skill or sport movement, and because the resistance vector cannot replicate the full and equal tangential resistance or velocity throughout the full functional arc and range of motion, this equipment has limited positive direct effect on performance. Functional and athletic motion is largely too variable, complex, and/or unpredictable for machines or any resistance training method to duplicate, including free weights and cable machines. If the combined dynamic training variables of a complex strength training movement do not exactly replicate the actual movement, the training may even be counter-productive in terms of performance enhancement. This may be secondary to interference with established complex neural patterns of movement. Attempting to replicate a particular complex functional motion with strength training does not result in a direct improvement in performance because of the specificity and complexity of the neuromuscular mechanism of movement and the mechanical limitations of strength training equipment. Thus, there is a clear need for strength training and strength testing equipment that provides resisted motion in the 360 degree radial array of simple planes of motion of the shoulder and other joints about multiple axes, as provided by the present invention.
The present invention provides important advantages over the prior art. First, this invention provides radial, exponential multiplane resistance exercise for both compound and isolated resisted motion of the shoulders or other joints of a user. Resistance exercise can be performed in all planes of the 360 degree radial array of planes of motion of a joint about multiple axes. Second, it can provide full and equal tangential resistance through the full arc and range of motion of exercise. Third, the present invention provides independent user interfaces for simulating functional movement. Fourth, the invention provides industry standard selectorized, electromechanical, and/or other resistance mechanisms or combinations of mechanisms. Fifth, it provides multiple-point or polygonal stabilization and restraint (e.g. triangular, rectangular, decagonal, and/or circular base of stabilization) of the boom and drive assembly, thereby providing multiple-point stabilization for the axis of rotation of the user interface(s) which pivot on the drive assembly. This provides a very stable platform through which symmetric and asymmetric forces generated by the user are transferred. Sixth, the present invention provides a new evidence-based paradigm for the use of this line of devices that includes a method for performing exercise in an exponential number of planes of motion, as well as a method for the transfer or integration of nonspecific strength training gains into functional movement.